<template>
  <el-container class="home-container">
    <!-- 头部区域  -->
    <el-header>
      <div>
        <img src="../assets/heima.png" alt="">
        <span>电商后台管理系统</span>
      </div>
      <el-button type="info" @click="logout">退出登录</el-button>
    </el-header>
    <!-- 页面主体区域 -->
    <el-container>
      <!-- 侧边栏 -->
      <el-aside :width="isCollapse ? '64px' : '200px'">
        <!-- 折叠展开按钮 -->
        <div class="toggle_button" @click="toggleCollapse">|||</div>
       <!--  侧边栏菜单区域 -->
        <el-menu background-color="#333744" text-color="#fff" 
                 active-text-color="#409eff" :unique-opened="true"
                 :collapse="isCollapse" :collapse-transition="false"
                 :default-active="activePath"
                 :router="true"><!-- 开启路由模式 -->
          <!-- 一级菜单 -->
          <el-submenu v-for="item in menuList" :key="item.id" :index="item.id + ''">
            <!-- 一级菜单模板区 -->
            <template slot="title">
              <!-- 图标 -->
              <i :class="iconsObj[item.id]"></i>
              <span>{{item.authName}}</span>
            </template>
          <!-- 二级菜单 -->
          <el-menu-item v-for="subItem in item.children" :key="subItem.id" 
                        @click="saveNavState('/' + subItem.path)"
                        :index="'/' + subItem.path"><!-- 通过路由地址跳转 -->
            <!-- 二级菜单模板区 -->
            <template slot="title">
              <!-- 图标 -->
              <i class="el-icon-menu"></i>
              <span>{{subItem.authName}}</span>
            </template>
          </el-menu-item>
          </el-submenu>
        </el-menu>
      </el-aside>
      <!-- 右侧内容主体 -->
      <el-main>
        <!-- 路由占位符 -->
        <router-view/>
      </el-main>
    </el-container>
  </el-container>
</template>

<script>
export default {
  name: 'Home',
  data() {
    return {
      //左侧菜单数据
      menuList: [],
      /* 根据id拿到对应的图标 */
      iconsObj: {
        '125': 'iconfont icon-user',
        '103': 'iconfont icon-tijikongjian',
        '101': 'iconfont icon-shangpin',
        '102': 'iconfont icon-danju',
        '145': 'iconfont icon-baobiao'
      },
      //是否折叠
      isCollapse: false,
      //被激活的链接地址
      activePath: ''
    }
  },
  created() {
    //页面刚一加载就获取左侧菜单数据
    this.getMenuList(),
    //页面一加载就让当前的列表默认保持高亮
    this.activePath = window.sessionStorage.getItem('activePath')
  },
  methods: {
    logout() {
      //清空token
      window.sessionStorage.clear()
      //再重定向到login页
      this.$router.push('/login')
      //提示消息
      this.$message('您已退出登录')
    },
    //获取所有的菜单
    async getMenuList() {
      //因为.get返回的是一个Promise 所以给await和async简化操作
      //{data: res} 通过解构赋值把data属性解构出来
      const {data: res} = await this.$http.get('menus')
      if(res.meta.status !== 200) return this.$message.error(res.meta.msg)
      this.menuList = res.data
      //console.log(res);
    },
    //点击按钮切换菜单的折叠与展开
    toggleCollapse() {
      this.isCollapse = !this.isCollapse
    },
    //保存链接的激活状态
    saveNavState(activePath) {
      window.sessionStorage.setItem('activePath', activePath)
      this.activePath = activePath
    }
  }
}
</script>

<style lang="less" scoped>
  .home-container {
    height: 100%;
  }
  .el-header {
    background-color: #373d41;
    display: flex;
    justify-content: space-between;
    padding-left: 0;
    align-items: center;
    color: #fff;
    font-size: 20px;
    > div {
      display: flex;
      align-items: center;
      span {
        margin-left: 15px;
      }
    }
  }
  .el-aside {
    background-color: #333744;
    .el-menu {
      border-right: none;
    }
  }
  .el-main {
    background: #eaedf1;
  }
  .iconfont {
    margin-right: 10px;
  }
  .toggle_button {
    background-color: #4a5064;
    color: #fff;
    font-size: 10px;
    line-height: 24px;
    text-align: center;
    letter-spacing: 0.2em;
    cursor: pointer;
  }
</style>